What is this?
Configuration of which entities "count" as one of the broad Enhanced AI categories, receiving the same abilities and AI tasks as those vanilla mobs.

Why?
To allow greater user customization and compatibility with modded entities. A user could configure husks, modded zombie variants, and other "humanoid"-like mobs to gain the Zombie features. A user could configure entities such as Quark's skeleton variant to gain the Skeleton features.

# Entities that gain Zombie features [default: ["minecraft:zombie"]]

This is basically something implemented as Black/Whitelist. The default list will be empty as defaults to blacklist.